Front End Board 16 channels

1
Superlayer Cross Section Frontend Enclosure
Front End Board (16 channels)
HV cap Board
Signals from chamber wires go to HV cap board to
be ground referred via 470 pF capacitors. Also
included in the PCB small (100?m) gaps to limit
high voltage peaks caused by discharges in the
detector. Signals are then available in 2 strips
of female sockets having a ground connection
every signal.
HV cap board
2
Frontend Boards
Frontend board
2 strips of male pins collect signals from HV cap
board after protection circuitry they are
processed by MAD ASICs and the results are
available at the connector in the center of the
board through which power supplies are also
carried. The small connector in the lower left
corner is used for the slow control bus (1 flat
cable for all the boards of 1 superlayer). Finger
springs provide ground connection to the cover
and heatsinking for the ASICs. A double
distribution of test pulses allows electric test
and simulation of traces at different positions
for trigger monitor. Input for this function can
be one of the two vertical strips of sockets in
the upper left and right corner.
3
Connections to Readout
1 fine pitch flat cable (40 wires) connects each
FE board to a feedtrhu PCB glued at the external
of the cover. From here signals go to readout
electronics through the blue connector. The
smaller flat cable is used for the 4 additional
signals of the 20 channel version of the FE
board. The feedthru PCB is connected to the power
supply bus bar via the small board soldered to
the flex jumper and feeds the FE board through
the signal flat cable. 2 Polyfuses (1 per
supply) limit excess current.
Feedthru PCB and output connector
4
Connections to monitors
One small board per superlayer acts as an
interface for Slow Control it buffers I2C bus
and provides predecoding function to address all
of the FE boards. It is glued to the cover of
the superlayer in the same way as the PCB of the
output connectors.
Slow Control interface
Test pulse distribution is made with small
splitter boards where impedance matching is
accurately cured. External signal comes to an
MCX connector placed on a small feedthru board on
the cover of the superlayer. Here its split on
2 cables going to other 2 small boards each one
placed across 2 FE boards in the upper corner.
In this way 1 external signal serves 4 boards.
5
Mock Up 1
Superlayer frame
Frontend bd. (old version)
Test Pulse splitter bd.
Out connector feedthru
Lodgement of P.S. bus bar
Slow Control Interface
Slow Control bus bar
Output P.S. flat cable
Superlayer cover 180o open
6
Mock Up 2 (test pulse)
4 frontend boards
Test Pulse splitter bd.
Test Pulse input connector and splitter
Test Pulse splitter bd.
7
Mock Up 3 (bus bar)
Connection from chamber wire to HV cap board
Flex jumper from bus bar to out conn
Power Supply bus bar
Test pulse cables
I2C predecoding bus
8
Mock Up 4 (closed superlayer top view)
Connection from chamber wire to HV cap board
Output flat cable bended
P.S. conn DIN M/2
Test Pulse MCX conn
Slow control interface
Output connector
Gas outlet
9
Mock Up 4 (closed superlayer bottom view)
Output connector
Gas Outlet
Water Outlet
HV cap board
P.S. bus bar
Slow Ctrl bus
10
Mock Up 4 (closed cover)
Power Supply connector
Output connectors for 20ch FE board